Uranium-lead, Rb-Sr, and Sm-Nd isotopic analyses have been performed on the same whole-rock, mineral, and leachate fractions of the basaltic martian meteorite Zagami to better constrain the U-Pb isotopic systematics of martian materials. Although the Rb-Sr and Sm-Nd systems define concordant crystallization ages of 166 ± 6 Ma and 166 ± 12 Ma, respectively, the U-Pb isotopic system is disturbed. Nevertheless, an age of 156 ± 6 Ma is derived from the 238U-206Pb isotopic system from the purest mineral fractions (maskelynite and pyroxene). The concordance of these three ages suggest that the 238U-206Pb systematics of the purest Zagami mineral fractions have been minimally disturbed by alteration and impact processes, and can therefore be used to constrain the behavior of U and Pb in the Zagami source region. The value of the Zagami source region can be estimated, with some confidence from the 238U-206Pb isochron, to be 3.96 ± 0.02. Disturbance of the U-Pb isotopic systems means that this represents a minimum value. The value of the Zagami source is significantly lower than the values estimated for most basaltic magma sources from Earth and the Moon. This is surprising given the high initial 87Sr/86Sr ratio (0.721566 ± 82) and low initial Nd value (7.23 ± 0.17) determined for Zagami that indicate that this sample is derived from one of the most highly fractionated reservoirs from any known planetary body. This suggests that Mars is characterized by a low bulk planet U/Pb ratio, a feature that is consistent with its relatively volatile-rich nature.

On an October afternoon in 1962, this meteorite landed about 10 feet away from a farmer who was trying to chase crows from his corn field. The farmer heard a tremendous explosion and was buffeted by a pressure wave. After a puff of smoke and a thud, the meteorite buried itself in a hole about 2 feet deep. Weighing at about 18,000 grams, the Zagami meteorite is the largest single individual Mars meteorite ever found.Read more

Zagami Mars Meteorite SaleA small Zagami slice with Fusion Crust that is currently on display in a Science Museum in the USA is to be put up for sale. The meteorite has been on display since June 1997 when it was loaned to the museum by an anonymous donor.The ten year loan agreement has finished, and the specimen is now shockingly up for sale.The owner, is looking for offers of $5400.00 for the 2.8 gram Zagami slice (inch long and half an inch wide).

The 18.1kg Zagami Mars Meteorite originally fell in 1962 October 3rd, near to Zagami rock, Nigeria, (11º44'N 7º5'E), landing about 10 feet away from a farmer who was trying to chase crows from his corn field. The Zagami meteorite is the most easily obtainable Achondrite, Shergottite (SNC); Basalt meteorite available to collectors.

Ed ~ i of course cannot endorse the removal of such a item, however minor, from the scientific community.